Data from: Reversible and size-controlled assembly of reflectin proteins using a charged azobenzene photoswitch

Disordered proteins often undergo a stimuli-responsive, disorder-to-order
transition which facilitates dynamic processes that modulate the
physiological activities and material properties of cells, such as
strength, chemical composition, and reflectance. It remains challenging to
gain rapid and spatiotemporal control over such disorder-to-order
transitions, which limits the incorporation of these proteins into novel
materials. The reflectin protein is a cationic, disordered protein whose
assembly is responsible for dynamic color camouflage in cephalopods.
Stimuli-responsive control of reflectin’s assembly would enable the design
of biophotonic materials with tunable color. Herein, a novel, multivalent
azobenzene photoswitch is shown to be an effective and non-invasive
strategy for co-assembling with reflectin molecules and reversibly
controlling assembly size. Photoisomerization between the trans and cis (E
and Z) photoisomers promotes or reduces Coulombic interactions,
respectively, with reflectin proteins to repeatedly cycle the sizes of the
photoswitch-reflectin assemblies between 70 nm and 40 nm. The protein
assemblies formed with the trans and cis isomers show differences in
interaction stoichiometry and secondary structure, which indi-cate that
photoisomerization modulates the photoswitch-protein interactions to
change assembly size. Our results high-light the utility of
photoswitchable interactions to control reflectin assembly and provide a
tunable synthetic platform that can be adapted to the structure, assembly,
and function of other disordered proteins.